Fix tgmath.h totalorder, totalordermag return type (bug 21687).

The tgmath.h totalorder and totalordermag macros wrongly return a
floating-point type.  They should return int, like the underlying
functions.  This patch fixes them accordingly, updating tests
including enabling tests of those functions from gen-tgmath-tests.py.

Tested for x86_64.

	[BZ #21687]
	* math/tgmath.h (__TGMATH_BINARY_REAL_RET_ONLY): New macro.
	(totalorder): Use it.
	(totalordermag): Likewise.
	* math/gen-tgmath-tests.py (Tests.add_all_tests): Enable tests of
	totalorder and totalordermag.
	* math/test-tgmath.c (F(compile_test)): Do not call totalorder or
	totalordermag in arguments of calls to those functions.
	(NCALLS): Change to 134.